1. Field of the Invention
The present invention relates to an elastic wave device in which a dielectric film is arranged between a piezoelectric substrate and an interdigital transducer (IDT) electrode.
2. Description of the Related Art
Elastic wave devices have been widely used as resonators and bandpass filters.
One example disclosed in Japanese Unexamined Patent Application Publication No. 2012-169707 below is an elastic wave device including a piezoelectric substrate, a dielectric layer disposed on the piezoelectric substrate, and first and second IDT electrodes laminated on the dielectric layer. In Japanese Unexamined Patent Application Publication No. 2012-169707, the electromechanical coupling coefficient of a used elastic wave is adjusted by changing the thickness of the dielectric layer disposed below each of the first and second IDT electrodes.
In the configuration of the elastic wave device in Japanese Unexamined Patent Application Publication No. 2012-169707, if static electricity generated by charging by friction or the like is applied to the IDT electrodes in a manufacturing step, a potential difference between the neighboring electrode fingers in the IDT electrodes is significantly large. This may result in electrostatic breakdown of the IDT electrodes.